Clean Diesel: Ultra Low Sulfur Diesel

The US EPA 2007 clean air regulations are fast approaching. Diesel users prepare for ULSD; but first, they need a few answers, writes Richard George.


To prevent this from reoccurring, nearly all engine manufacturers have changed gaskets to materials less susceptible to changes in aromatic content, which should prevent an outbreak like in 1993, but it is still worth watching. Fleet vehicles that are dedicated to a single source of fuel may be more likely to develop problems from a fuel change than vehicles that commonly get a variety of fuel. If leaks develop, the solution is usually just a new gasket.

The Availability of ULSD

So when will this fuel be available? Some ULSD is in the market now, but don’t expect to see much of it before the second half of this year. Stations will be required to label their pumps as ULSD or LSD to prevent misfueling of the new 2007 vehicles. It’s these 2007 model year vehicles and any vehicles retrofitted with exhaust aftertreatment devices that are required to use it. Most others vehicles can use either LSD or USLD fuel. With approximately 90 percent of U.S. diesel production as ULSD, it should be available everywhere. Some regions like the Northeast may be more challenging for suppliers, since the Northeast relies heavily on pipeline shipments from the Gulf Coast. Texas to New Jersey is a long way to move ULSD without contamination. Eventually the bugs will be worked out of the distribution systems and demand will increase as newer vehicles appear on the road, so all areas should have an ample supply of ULSD.

What about customers that want to continue to use the current LSD? LSD will still be available, but it might be the harder of the fuels to find at retail. If the concern is about fuel economy, lubricity or seal swell, it may not be worthwhile to hunt for LSD. Much of the LSD in the market after the ULSD rollout might simply be “off-spec” ultra low. If ULSD is contaminated with just a little sulfur, it will be downgraded to LSD. This LSD will have ULSD-like properties and will not be the same old LSD you are using now.

So again, ULSD is coming. It is going to be a headache for producers and distributors, but hopefully not for the end users. Any problems encountered in the next year or so, whether related or not, could be blamed on ULSD, and this may send users looking for their old fuel. If all goes well, it will lead to less vehicle emissions and hopefully will shake diesel of its stinky, dirty image. This clean diesel could lead the way for more light-duty diesel cars and trucks with better fuel economy than their gasoline counterparts. Better fuel economy truly means less emissions and less dependence on crude oil. This is a big step for diesel fuel, the petroleum industry and the environment.

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